Hi, I know I am in the wrong place but have recently got a 2009 Audi A4. This has no sat nav, just the Symphony stereo and I would like to install sat nav. The Alpine complete retrofit is over £1500 so the idea of simply overlaying carplay seems tempting. Searched the internet and this thread continually comes up as the most vocal and informative on the subject. Appreciate you are all A5 owners, but does anyone know if this solution will work for A4 and also if the China or RSNav options are the same as that sold by Unique Auto Developments in the uk? It looks and sounds the same though they claim to also include a touch screen overlay. Finally, does anyone know anywhere in or around North London that would install this? I know it is supposed to be plug and play but am not too keen on taking the car apart myself. Thanks for any advice.